Diamond holder for 180 degree concave radii in grinding wheels



pril 1, 1952 CONCAVE W. MUENCH DIAMOND HOLDER FOR 180 DEGREE RADII IN GRINDING WHEELS Filed March 21, 1947 Patented Apr. 1, 1952 DIAMOND HOLDER FOR 180 DEGREE CON CAVE RADII IN GRINDING WHEELS Walter Muench, Newark, N. J., assignor to Walter Muench, Incorporated, Newark, N. J a corporation ofNew Jersey Application March 21, 1947, Serial No. 736,222

4 Claims.

My invention relates generally to diamond carrying tools, and in particular to that category used to form'in the periphery of a grinding wheel concave radii to produce fully 180 degree half circle contour arcs.

To produce in a grinding wheel a half circle concave contour of say width, the tool part holding the diamond should not be much smaller than 1%" diameter in order to retain strength and stability in the tool.

A e" diameter straight tool would be a fairly good size of a tool, but even at this diameter would chatter, and vibrations would be set up in the tool part adjacent the diamond, as the side thrust of the grinding wheel, revolving at 3500 revolutions per minute, is very great when the tool-forming a "1 2;" diameter concave half circle; especially if the diamond carrying tool part is extremely long. Consequently faulty and out-ofform contours are the result, and what is in the wheel will later on be transferred to whatever work has to be ground by the wheel.

The smaller the half circle desired in a grinding wheel periphery, the smaller the diameter of the usual form of diamond holding part must be.

Therefore, such a diamond holding part set toform a I radius half circle cannot be more than in diameter at any point near where the diamond is mounted.

Quite naturally, the smaller in diameter the diamond holding part has to be, the greater the chatter will be and with consequent greater distortion in the contour of the half circle in the wheel periphery.

All diamond holding tools now in use for small concave contour forming in the periphery of a grinding Wheel, of which I am aware, consist of long, frail, straight or slightly tapered rods, which are held in a socket under the pressure of a tiny set screw, and these insecure means of holding the long frail rods in their respective places increase the vibrations of the tool when in operation and thereby add to the already unstable performance of a weak tool rod.

To overcome these defects in the design and structure of the tools now used to produce small concave radii from 19? up to 1 s" in the periphcry of any diameter grinding wheel is the purpose of 'my'invention, and I attain these objects by a special design illustrated in the accompanying drawing, in which:

Figure 1 is a side view of my improved diamond carrying tool.

Figure 2 is a top view of the tool shown in Figure '1.

Figure 3 is a bottom view of the tool shown in Figure 1.

Figure 4 is a vertical section on the line X Y on Figure 1.

Figure 5 is a reduced scale side view of a grinding wheel showing a diamond holding tool in contact with'the wheel at the moment of finishing a concave radius.

Figure 6 is a sectional view on the center line cd of Figure 5, showing the concave radius formed in the periphery of the grinding wheel.

Referring now to the drawings in which similar numerals refer to similar parts throughout the several views, I is a solid shank to which is cast the diamond carrying arm 2.

At the longer end of the arm '2 a small industrial diamond 5 is brazed in place, while the shorter end of the arm 2 is reserved in readiness for the application of any desired measuring device.

Eighty percent of all grinding wheels used in the United States in connection with the con- 'ventional tool room surface grindersfor all sorts of grinding, including that of convex and concave radii, are seven inches in diameter, while the other 20% are divided somehow, using 4 and 10" diameter wheels.

On this basis the diamond holding arm needs to be, in each particular instance, really only as long as is absolutely necessary to avoid the possibility that the wheel might grind into the shank I When the swivel arm of the radius dressing fixture in which the shank with its diamond holding arm is securely held comes to the end stop of a swing: both left and right side.

The shorter the diamond holding arm of the tool the less are the possibilities of the diamond developing objectionable chatter when forming small concave radii in grinding Wheels.

To make the diamond holding arm of the tool to a predetermined, precise calculated necessary length for all 4", '7" and 10" diameter wheels, as far as the forming of small concave radii in grinding wheels is concerned is therefore another part of my invention.

To merely make the tool arm short for the purpose in question would not of itself make a perfect and chatterless diamond holding tool.

For instance, to form a 3AM," radius full half circle, the maximum permissible diameter at the very point where the diamond is brazed in the tool arm must not be more than twice the size 3 of that of the radius desired in the wheel, in this case 3%".

Following the above stated example as regards sizes, it has been, up to now, the custom in a case like this to simply take a 3%" straight rod, put a chip of a diamond in one end and let it go at that.

In very few cases did it occur to the makers of diamond tools to furnish slightly tapered rods, and then they did it without any definite aim as to the length of the tool, and in utter disregard of the diameter the larger end could have been increased to give the tool the necessary strength.

To make the extensive requirements for a chatterless diamond holding arm in a tool very clear, further explanations are necessary.

Holding again to the exemplary diameter of at the point of the diamond, it would seem logical to merely use a thick plate, and by increasing it from a diameter point at the diamond seat to a full A width towards the shank to give it extra support, as shown in Figure 2, a tool would thereby be produced which could be used.

Careful observation and much experimenting with this problem has proven however that in such a 7 thick flat plate arm, constructed as stated above, much chatter is set up at the point of the diamond, due to the twisting action of the grinding wheel when the diamond is in the process of forming a /64" radius in the periphery of a grinding wheel.

To strengthen this thick flat plate, or as a matter of fact all sizes up to a radius is still another part of my invention and I attain this object by providing a tapering rib, solidly cast under the thick plate and of such width as to meet all functional limitations.

A cross section of the thus strengthened diamond carrying arm on the line X-Y of Figure 1 is shown in Figure 4, and with this structure all vibrations are reduced to a negligible minimum.

As regards Figure 5, it is intended to show how the necessary length of the diamond holding arm in relation to the positioning of the shank in the one piece cast tool is calculated, not only in reference to the size of the half circle contour that is to be produced in the grinding wheel, but also in respect to the changing conditions that will appear if the shank diameters may have to 2.

be increased or decreased in some cases in order to conform to the mechanical arrangements which vary in many of the radius dressing fixtures now in use in the United States.

The position the tool is in, in Figure 5, coincides in general with that which is shown in the bottom view of Figure 3.

To calculate the measurement required for the length of the diamond holding arm, that is, from the center of the diamond to the center of the shank, so that in forming any given radius the grinding wheel does not cut into the shank of the tool, tabulated trigonometric formulas could be worked out but it is by no means necessary to resort to such means as it even might lead to complications rather than clarification of the subject.

Referring again to Figure 5, here an example is put down for a grinding wheel in a simple geometrical layout that can be followed for any diameter wheel.

The spot where the vertical axis c--d meets the horizontal Z-k can be considered the center at which the diamond point first comes in contact with the wheel, and during the process of gen-' diameter crating the A radius contour in the wheel, the diamond holding arm moves A" deep into the periphery of the wheel.

Considering now the horizontal lk as an established horizontal center line for the tool arm 2, it is obvious that the shank which is in diameter can be located with its axis in the same horizontal plane in which said line Z-k lies and with the circle of the shank cross section just outside the periphery of the grinding wheel.

Measuring now with an accurate tool makers scale from the vertical axis cd to the vertical center line m-n drawn through the diameter circle indicating the diameter shank 2, a measurement of 1 is obtained, which then is the predetermined calculated proper length of the diamond holding arm 2 of the tool proper.

When larger shanks are desired, as for instance a diameter, the outline of which is indicated in the drawing by a dotted line 6, with its vertical center op then the proper length of the diamond holding arm 2 increases to approximately Once these proper lengths of the diamond holding arms are calculated for the different diameter wheels in use, they can be considered a standard for all sizes of concave radii, whether small or large.

The only thing that will vary is the front end at the diamond point, showing a somewhat altered curve sweep at the sides and the bottom rib towards the shank. This changed curve sweep is indicated in the drawing for a 1%" concave radius diamond tool by the dot and dash line 2.

It should also be stated that it is common practice in industry to wear a 7 diameter grinding wheel down to about 4 diameter when it is discarded, as the surface speed at this small diameter is greatly reduced so that it becomes uneconomical to use it any longer in a surface grinder that is built to take a 7" diameter wheel.

When, as in this case, the 7" diameter wheel is finally worn down to a 4 diameter, but is considered still good enough for contour grinding at least, then it is advisable by all means to use for any concave contour dressing in these wheels the diamond carrying tools which are especially made for a 4" diameter wheel, as the proper length of the diamond holding arm for a 4" diameter wheel is so much shorter than the one made for a '7 diameter wheel.

The shorter the diamond holding arm, the better because the shorter the tool, the less chatter is set up in operation, and a more accurate concave contour can be expected in the grinding wheel when the precautions are taken of always using the shortest tool possible.

It should be understood that a diamond carrying tool made for a 4" diameter wheel cannot be used with a 7" and 10 diameter wheel.

Also, a diamond carrying tool made for use with a 7" diameter wheel cannot be used with a 10 diameter wheel, but a diamond carrying tool made for a '7" diameter wheel can be used with a 4" diameter wheel and one made for a 10" diameter wheel can be used with a 4" diameter wheel as well as with a 7" diameter wheel if need be.

While I have illustrated and described my invention with some degree of particularity, I realize that in practice various alterations herein may be made. I, therefore, reserve the right and privilege of changing the form of the details and construction or otherwise altering the arrangement of the correlated parts without departing from the spirit of the invention or the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

l. A tool adapted for presenting a diamond in position for cutting concave grooves in the peripheries of grinding wheels, said tool consisting of an elongated carrier body and an elongated mounting shank, the length centers of said body and shank bearing perpendicular relation and said shank projecting from said body adjacent one end thereof, a wheel periphery cutting diamond mounted on and projecting from the body adjacent the end thereof remote from the shank and in a direction paralleling the length center of the shank and opposite the direction of projection of said shank, said body gradually increasing in thickness from the diamond carrying end to the shank carrying end to provide side recesses in which to receive portions of wheels being grooved and thus permit said recessed body'sides to closely approximate wheel peripheries during grooving thereof, and said body including a flat plate-like body having concave side edges shaped to substantially conform to the periphery of a wheel being grooved by the tool, and a depending rib increasing in depth from the diamond carrying end toward the shank and having sides spaced inwardly from and conforming in curvature to the sides of said plate like body.

2. A tool adapted for presenting a diamond in position for cutting concave grooves in the peripheries of grinding wheels, said tool consisting of an elongated carrier body and an elongated mounting shank, the length centers of said body and shank bearing perpendicular relation and said shank projecting from said body adjacent one end thereof, a wheel periphery cutting diamond mounted on and projecting from the body adjacent the end thereof remote from the shank and in a direction paralleling the len th center of the shank and opposite the direction of projection of said shank, said body gradually increasing in thickness from the diamond carrying end to the shank carrying end to provide side recesses in which to receive peripheral portions of wheels being grooved and thus permit said recessed body sides to closely approximate wheel peripheries during grooving thereof, and said body including a fiat plate-like body having concave side edges shaped to substantially conform to the periphery of a wheel being grooved by the tool, and a depending rib increasing in depth from the diamond carrying end toward the shank and having sides spaced inwardly from and conforming in curvature to the sides of said platelike body, said rib starting in a sharp point beneath the diamond and the concave sides of said rib merging into said point.

3. A tool adapted for presenting a diamond in position for cutting concave grooves in the peripheries of grinding wheels, said tool consisting of an elongated carrier body and an elongated mounting shank, the length centers of said body and shank bearing perpendicular relation and said shank projecting from said body adjacent one end thereof, a wheel periphery cutting diamond mounted on and projecting from the body adjacent the end thereof remote from the shank and in a direction paralleling the length center of the shank and opposite the direction of projection of said shank, said body gradually increasing in thickness from the diamond carrying end to the shank carrying end to provide side recesses in which to receive peripheral portions of wheels being grooved and thus permit said recessed body side to closely approximate wheel peripheries during grooving thereof, and said body including a fiat plate-like body having concave side edges shaped to substantially conform to the periphery of a wheel being grooved by the tool, and a depending rib increasing in depth from the diamond carrying end toward the shank and having sides spaced inwardly from and conforming in curvature to the sides of said platelike body, said rib starting in a sharp point beneath the diamond and the concave sides of said rib merging into said point, and said shank being of a thickness for lying between and not extending laterally beyond said concave rib sides.

4. A tool adapted for presenting a diamond in position for cutting concave grooves in the peripheries of grinding wheels, said tool consisting of an elongated carrier body and an elongated mounting shank, the length centers of said body and shank bearing perpendicular relation and said shank projecting from said body adjacent one end thereof, a wheel periphery cutting diamond mounted on and projecting from the body adjacent the end thereof remote from the shank and in a direction paralleling the length center of the shank and opposite the direction of projection of said shank, said body gradually increasing in thickness both as to width and depth as it extends away from the end thereof carrying the diamond and toward the shank, the gradual increase widthwise extending all the way to the location of the shank and being in the form of concave sides with the radius of each concave side conforming generally to the radius of a wheel periphery to be grooved by the tool so that either concave side can conform generally to the curvature of the periphery of a wheel being grooved by the diamond during a portion of the grooving, and the gradual increase depthwise being progressively extended from the position of the diamond at least part way toward said shank, and said shank being of a thickness for lying between and not extending laterally beyond said concave sides.

WALTER MUENCH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,772,042 Helm Aug. 5, 1930 2,082,736 Indge June 1, 1937 2,127,614 Parker Aug. 23, 1938 2,293,749 ONeill Aug. 25, 1942 FOREIGN PATENTS Number Country Date 554,875 Great Britain July 22, 1943 

